Patient education: Brain death (The Basics)

What is brain death? — 

This is when all brain activity stops. The brain cannot control the body's functions or respond to anything. Brain death happens after an injury to the brain or when there is a period of no blood flow to the brain. Without blood flow, the brain cannot get oxygen, which it needs to survive. Brain death is not reversible.

Brain death can be hard to understand. Sometimes, it happens at the same time as the heart stops beating. Other times, the person might seem to be "alive." For example, their skin is warm and they look like they are breathing. But this is because they are on artificial life support.

Artificial life support measures include:

●Medicines to keep blood pressure up

●A ventilator – This is a machine that controls breathing.

●Fluids given through a thin tube that goes into a vein, called an "IV"

In the US and many other countries, when a person is officially diagnosed as brain dead, they are considered to be legally dead.

What causes brain death? — 

Many things can cause it. Examples include:

●Trauma to the head from an accident, fall, or injury

●A stroke

●Lack of oxygen to the brain – This might happen because of a heart attack or drowning.

How is brain death different from a coma or persistent vegetative state? — 

People with brain death have no brain activity at all. But people in a coma or in a "persistent vegetative state" have some brain activity:

●Coma – This is a deep state of unconsciousness. A person in a coma looks like they are asleep, but they cannot be woken up. They cannot move on their own and don't respond or react to pain, being touched, or shaken. Not all people who are in a coma are on life support. Some people wake up from a coma, but others do not. People in a coma have minimal brain activity, whereas people with brain death have no brain activity.

●Persistent vegetative state – This is also called "unresponsive wakefulness syndrome." It usually occurs in patients who had a severe brain injury causing a coma. As a person wakes up from a coma, they might open their eyes. Their brain activity suggests they go to sleep and wake up. But they are unaware of and cannot react to their surroundings. They might be able to swallow and breath on their own. While some degree of recovery is possible, the longer a person is in this condition, the less likely they are to recover.

Is there a test for brain death? — 

Yes. Doctors can use different tests to check for brain death. The tests are done under very specific conditions to make sure the results are accurate.

Before testing, the doctor will learn about the person's health history and any injuries. They will also:

●Check if they had a test that shows brain problems

●Correct problems that might impact brain function. Examples include:

•Very high or low blood sugar

•Poor blood flow to organs and tissues

•Abnormal blood tests

●Check if they are on any sedation medicines – The doctor will stop these medicines for a time to let them clear from the person's body.

●Make sure they have a normal temperature and blood pressure

The doctor will also do a detailed exam to see how the person responds to touch and pain. They will also check for:

●Breathing – People with brain death cannot breathe on their own.

●Reflexes – People with brain death do not have normal reflexes. They cannot blink, gag, or cough.

●Movement – People with brain death cannot move on their own. They might twitch a little or make other unintentional movements.

●Pupils that respond to light – The pupils of people with brain death do not respond to light.

Often, more than 1 doctor will check the person to make sure the tests are correct. They might also repeat the tests.

Sometimes, other tests are done as well. Examples include:

●Electroencephalogram ("EEG") – This measures electrical activity in the brain. People with brain death have no detectible electrical activity.

●Imaging tests to look for blood flow in the brain – These create pictures of the inside of the brain. People with brain death have no blood flow in the brain.

What happens when a person has brain death? — 

After doctors determine a person does have brain death, they will explain the person is legally dead and declare a time of death. The person will not recover or wake up.

The doctors will help you understand what the next steps are for your loved one. They can help connect you with support and resources. In some cases, a person's organs can be donated.

More on this topic

Patient education: Hypoxic brain injury (The Basics)
Patient education: Moderate to severe traumatic brain injury (The Basics)
Patient education: Stroke (The Basics)
Patient education: Coma (The Basics)
Patient education: EEG (The Basics)
Patient education: Advance directives (The Basics)

Patient education: Stroke symptoms and diagnosis (Beyond the Basics)